A new study conducted by researchers at the University of Maine has found significant changes in the habitats and demographics of American lobsters along the Maine coast. From 1995 to 2021, the occupancy of traditional boulder shelter habitats declined by 60%, while lobsters increasingly took up residence in less sheltered environments, such as sediment and featureless ledges, with increases of 633% and 280%, respectively. Overall population density has also decreased, indicating a more spread-out and aging lobster population.
Researchers noted a nearly 3 degrees Celsius rise in water temperatures during this period, contributing to the shifts in lobster habitat usage. Kelp abundance has decreased, while algal turfs have proliferated. This change in habitat preference—less reliance on rocky shelters and a move towards open spaces—may be attributed to reduced competition, predator avoidance, and a decline in the survival of juvenile lobsters.
Interestingly, while the total population density has dropped, the average size of adult lobsters has increased since 1996, likely due to fewer juveniles in the population. However, 93% of lobsters remain below the legal catch size of 83 millimeters, suggesting a potential for future fishery sustainability.
The study underscores the dynamic nature of one of the world’s most commercially important marine species and highlights the ongoing efforts by UMaine to support Maine’s blue economy through sustainable management practices and innovative research to address climate change impacts.
